Oxygen Vacancy Induced Room-Temperature Metal–Insulator Transition in Nickelate Films and Its Potential Application in Photovoltaics

Wang, Le; Dash, S.; Chang, Lei; You, Lü; Feng, Yaqing; He, Xu; Jin, Kui; Zhou, Yang; Ong, Hock Guan; Ren, Peng; Wang, Shiwei; Chen, Lang; Wang, Junling

doi:10.1021/acsami.6b00650

Cited by 108 publications

(115 citation statements)

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“…Oxygen vacancies (V O s), as one of the most common ion defects, can be effectively employed to tune the functionality of transition metal oxides 5 such as superconductivity of cuprates 6 , induced polarization 7, 8 , metal-insulator transitions 9–11 and distinct chemical expansion 12 . Specifically, it is considered that the dynamic behaviour of V O s, especially the electromigration of V O s, determines the performance of oxide-based electroresistive memories.…”

Section: Introductionmentioning

confidence: 99%

Atomic-resolution imaging of electrically induced oxygen vacancy migration and phase transformation in SrCoO2.5-σ

Zhang

Shi

et al. 2017

Nat Commun

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Oxygen ion transport is the key issue in redox processes. Visualizing the process of oxygen ion migration with atomic resolution is highly desirable for designing novel devices such as oxidation catalysts, oxygen permeation membranes, and solid oxide fuel cells. Here we show the process of electrically induced oxygen migration and subsequent reconstructive structural transformation in a SrCoO2.5−σ film by scanning transmission electron microscopy. We find that the extraction of oxygen from every second SrO layer occurs gradually under an electrical bias; beyond a critical voltage, the brownmillerite units collapse abruptly and evolve into a periodic nano-twined phase with a high c/a ratio and distorted tetrahedra. Our results show that oxygen vacancy rows are not only natural oxygen diffusion channels, but also preferred sites for the induced oxygen vacancies. These direct experimental results of oxygen migration may provide a common mechanism for the electrically induced structural evolution of oxides.

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Section: Introductionmentioning

confidence: 99%

Atomic-resolution imaging of electrically induced oxygen vacancy migration and phase transformation in SrCoO2.5-σ

Zhang

Shi

et al. 2017

Nat Commun

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“…Oxygen vacancies, which are intrinsic to perovskite oxides, play a major role in the electronic and magnetic properties of strongly correlated systems. These vacancies effectively act as double electron donors, tuning the valence states of B-site transition metal cations in ABO 3 perovskite oxides [17]; as a consequence, the magneto-transport properties of these films are strongly impacted [18]. For instance, in La 0.5 Sr 0.5 CoO 3 − x perovskite thin films, the negative MR value sharply increased from 1 to 17% when the oxygen partial pressure during the thin film growth changed from 1 to 0.1 mbar [19].…”

Section: Introductionmentioning

confidence: 99%

Magnetoresistance Versus Oxygen Deficiency in Epi-stabilized SrRu1 − x Fe x O3 − δ Thin Films

et al. 2017

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Oxygen vacancies have a profound effect on the magnetic, electronic, and transport properties of transition metal oxide materials. Here, we studied the influence of oxygen vacancies on the magnetoresistance (MR) properties of SrRu1 − xFexO3 - δ epitaxial thin films (x = 0.10, 0.20, and 0.30). For this purpose, we synthesized highly strained epitaxial SrRu1 − xFexO3 − δ thin films with atomically flat surfaces containing different amounts of oxygen vacancies using pulsed laser deposition. Without an applied magnetic field, the films with x = 0.10 and 0.20 showed a metal–insulator transition, while the x = 0.30 thin film showed insulating behavior over the entire temperature range of 2–300 K. Both Fe doping and the concentration of oxygen vacancies had large effects on the negative MR contributions. For the low Fe doping case of x = 0.10, in which both films exhibited metallic behavior, MR was more prominent in the film with fewer oxygen vacancies or equivalently a more metallic film. For semiconducting films, higher MR was observed for more semiconducting films having more oxygen vacancies. A relatively large negative MR (~36.4%) was observed for the x = 0.30 thin film with a high concentration of oxygen vacancies (δ = 0.12). The obtained results were compared with MR studies for a polycrystal of (Sr1 − xLax)(Ru1 − xFex)O3. These results highlight the crucial role of oxygen stoichiometry in determining the magneto-transport properties in SrRu1 − xFexO3 − δ thin films.

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“…

into the corner-shared NiO 6 octahedra network (Figure 1a) modifies the NiO bond length and angle, affecting the electronic bandwidth and physical properties of RNiO 3 . [2,10] Previous works have shown that oxygen vacancies play an important role in perovskite heterostructures. [2,10] Previous works have shown that oxygen vacancies play an important role in perovskite heterostructures.

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confidence: 99%

Electrochemically Driven Giant Resistive Switching in Perovskite Nickelates Heterostructures

Wang

Zhang

Chang

et al. 2017

Adv Elect Materials

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into the corner-shared NiO 6 octahedra network (Figure 1a) modifies the NiO bond length and angle, affecting the electronic bandwidth and physical properties of RNiO 3 . Furthermore, Ni 3+ is reduced2 2x and electrons are doped into RNiO 3 via oxygen vacancies. [2,10] Previous works have shown that oxygen vacancies play an important role in perovskite heterostructures. [10][11][12][13][14][15] External electric field could induce the migration of the oxygen vacancy in the perovskite films and then change the interfacial barrier in heterostructures, leading resistive switching (RS) behavior. We expect such effect to be more prominent in nickelates-based ones due to their smaller oxygen vacancy formation energy. This motivates us to explore the possibility of electrochemically driven RS in nickelates systems. Our finding reveals giant bipolar RS behavior in Pt/RNiO 3 / Nb-SrTiO 3 heterostructures with ON/OFF ratio of about 10 5 at room temperature. The effect is tunable by varying the oxygen content or changing the rare earth element in the sample.A set of GdNiO 3−x films on Nb-SrTiO 3 substrates were grown under different deposition oxygen pressures (P(O 2 )) of 100, 20, 2, and 0.2 mTorr, respectively. The film thickness was fixed at 10 nm. The samples are labeled as D1-D4, in the order of decreasing P(O 2 ) from 100 to 0.2 mTorr. The influence of P(O 2 ) on our samples can be seen in Figure 1 (also see Figure S1 in the Supporting Information). Figure 1b displays the typical current-voltage (I-V) characteristics of the samples, and the inset is the schematic setup for the measurements. The arrows in Figure 1b represent the sequence of voltage sweeps. Sample D1 shows nonlinear I-V characteristics with negligible RS effect. In contrast, sample D4 shows obvious "counterclockwise" bipolar RS behavior. Here, we define the upper and lower branches of the I-V curves as low resistance state (LRS or ON) and high resistance state (HRS or OFF), respectively. Sample D4 switches from HRS (LRS) to LRS (HRS) when a forward (reverse) bias is applied to Pt, and this is defined as the set (reset) process. It should be pointed out that this counterclockwise I-V hysteresis in our asymmetrical devices is different from ferroelectric switchable diode behavior, [16][17][18] which is mainly controlled by the ferroelectric polarization. Since the formation energy of oxygen vacancy is low in nikelates, [9] we expect more oxygen vacancies in the GdNiO 3−x film than in the Nb-SrTiO 3 substrate. Scanning transmission electronThe rich phase diagrams and peculiar physical properties of rare earth perovskite nickelates (RNiO 3 ) have recently attracted much attention. Their electronic structures are highly sensitive to carrier density and bandwidth due to Mott physics. Here, the electrochemically driven giant resistive switching in Pt/RNiO 3 /Nb-SrTiO 3 heterostructures is reported. Systematic investigation confirms that oxygen vacancies migration modifies the interfacial barrier at the RNiO 3 /Nb-SrTiO 3 interface and causes the resistive swit...

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Oxygen Vacancy Induced Room-Temperature Metal–Insulator Transition in Nickelate Films and Its Potential Application in Photovoltaics

Cited by 108 publications

References 49 publications

Atomic-resolution imaging of electrically induced oxygen vacancy migration and phase transformation in SrCoO2.5-σ

Atomic-resolution imaging of electrically induced oxygen vacancy migration and phase transformation in SrCoO2.5-σ

Magnetoresistance Versus Oxygen Deficiency in Epi-stabilized SrRu1 − x Fe x O3 − δ Thin Films

Electrochemically Driven Giant Resistive Switching in Perovskite Nickelates Heterostructures

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